The light emitting device, for an example, a light emitting diode, is a kind of semiconductor device which converts electric energy to a light and is spot lighted as a next generation light source, replacing the present fluorescent lamps and incandescent lamps.
Since the light emitting diode generates the light by using the semiconductor device, the light emitting diode consumes power very lower than the incandescent lamp which generates the light by heating tungsten or the fluorescent lamp which generates the light by making an UV beam generated from high voltage discharge to hit a phosphors.
And, since the light emitting diode generates the light by using a potential gap of the semiconductor device, the light emitting diode has a long lifetime, and a fast response characteristic, and is environment friendly.
Accordingly, there have been many researches for replacing the present light sources with the light emitting diodes, and, as a result of those, application of the light emitting diodes to lighting devices, such as different lamps used at indoor and outdoor, liquid crystal display apparatus, electric sign boards, street lamps and so on as light sources thereof, is increasing.